基于NSGA2遗传算法的地铁隧道上方基坑工程优化设计

为在有效控制基坑下覆地铁隧道竖向位移的情况下,尽可能地减小基坑工程造价,基于NSGA2遗传算法,以5个基坑工程控制下覆地铁隧道竖向位移的关键设计参数为优化设计变量、隧道最大竖向位移和工程造价中的可变值为优化目标,优化得到Pareto最优解集。结合专家打分-COWA算子-博弈论组合赋权法和TOPSIS法从Pareto最优解集中选出最佳方案,并分析专家打分的主观权重改变对最佳方案的设计变量、目标函数值等参数的影响。研究结果表明:最佳方案比初始方案的隧道最大竖向位移减少23.3%,工程造价中的可变值减少36.9%,证明本文对地铁隧道上方基坑工程优化设计方法的有效性。

Optimization design for foundation pit above metro tunnel based on NSGA2 genetic algorithm

To effectively control the vertical displacement of the metro tunnel under the foundation pit and reduce the construction cost of the foundation pit as much as possible,based on NSGA2 genetic algorithm,the Pareto optimal solution set was obtained by taking 5 key design parameters of the foundation pit controlling the vertical displacement of the underlying metro tunnel as the optimal design variables,the maximum vertical displacement of the tunnel and the variable value of construction cost as the optimization objectives.Combining the expert scoring-COWA operator-game theory combination weighting method and TOPSIS method,the optimal scheme was selected from Pareto optimal solution set,and the effect on the change of the subjective weight of expert scoring on the design variables,objective function values and some other parameters of the best scheme were analyzed.The results show that the maximum vertical displacement of the tunnel in the best scheme is 23.3%less than that in the initial scheme,and the variable value of construction cost is 36.9%less than that in the initial scheme.It proves the effectiveness of the optimization design method for the foundation pit above the metro tunnel.